Chair control for synchronized movement of chair seat and back, and chair having same

Abstract

A chair seat adjustment mechanism has a support, a back bracket for attachment to a chair back and a seat plate for attachment to a chair seat. The back bracket is pivotally mounted to the support at a first pivot. The seat plate, which extends above the support, is pivotally mounted to the back bracket at a second pivot and slidably hinged to the support at a third pivot. The second pivot is positioned above and rearwardly of the first pivot. The third pivot is positioned forwardly of the second pivot such that rearward titling of the back bracket draws the seat plate rearwardly and tilts a rear of the seat plate downwardly. The third pivot may be a pivot pin on the support slidably received in an elongate slot on the seat plate, which may be slightly declined towards the back. A chair having such a chair seat adjustment mechanism is more comfortable for some users.

1 . A chair seat adjustment mechanism, comprising: 
 a support;    a back bracket for attachment to a chair back, said back bracket pivotally mounted to said support at a first pivot;    a seat plate extending above said support, said seat plate for attachment to a chair seat, said seat plate pivotally mounted to said back bracket at a second pivot and slidably hinged to said support at a third pivot,    said second pivot positioned above and rearwardly of said first pivot and said third pivot positioned forwardly of said second pivot such that rearward titling of said back bracket draws said seat plate rearwardly and tilts a rear of said seat plate downwardly.    
   
   
       2 . The mechanism of  claim 1 , wherein one of said seat plate and said support defines an elongate slot, and wherein said third pivot comprises a pivot pin on the other of said seat plate and said support slidably received in said slot, such that said seat plate is slidably hinged at said pivot pin.  
   
   
       3 . The mechanism of  claim 2 , wherein said slot is shaped and oriented to allow reciprocal movement of said seat plate when said back bracket is pivoted about said first pivot.  
   
   
       4 . The mechanism of  claim 1 , wherein said back bracket is normally biased towards a forward position.  
   
   
       5 . The mechanism of  claim 1 , wherein at least one of said seat plate and said back bracket is generally channel-shaped and is nested with said support.  
   
   
       6 . A chair comprising: 
 a seat;    a back;    a support;    a back bracket attached to said back, said back bracket pivotally mounted to said support at a first pivot; and    a seat plate attached to said seat and extending above said support, said seat plate pivotally mounted to said back bracket at a second pivot and slidably hinged to said support at a third pivot,    said second pivot positioned above and rearwardly of said first pivot and said third pivot positioned forwardly of said second pivot such that rearward titling of said back draws said seat rearwardly and tilts a rear of said seat downwardly.    
   
   
       7 . The chair of  claim 6 , wherein one of said seat plate and said support defines an elongate slot, and wherein said third pivot comprises a pivot pin on the other of said seat plate and said support slidably received in said slot, such that said seat plate is slidably hinged at said pivot pin.  
   
   
       8 . The chair of  claim 7 , wherein said slot is shaped and oriented to allow reciprocal movement of said seat plate when said back bracket is pivoted about said first pivot.  
   
   
       9 . The chair of  claim 8 , wherein said back bracket is normally biased towards a forward position.  
   
   
       10 . The chair of  claim 6 , wherein at least one of said seat plate and said back bracket is generally channel-shaped and is nested with said support.  
   
   
       11 . A chair seat adjustment mechanism, comprising: 
 support means for supporting a chair seat and a chair back;    first attachment means for attaching to said chair back, said first attachment means pivotally mounted to said support means at a first pivot means; and    second attachment means for attaching to said chair seat, said second attachment means extending above said support means, said second attachment means pivotally mounted to said first attachment means at a second pivot means and slidably hinged to said support means at a third pivot means,    said second pivot means positioned above and rearwardly of said first pivot means and said third pivot means positioned forwardly of said second pivot means such that rearward titling of said first attachment means draws said second attachment means rearwardly and tilts a rear of said second attachment means downwardly.    
   
   
       12 . A chair seat adjustment mechanism, comprising: 
 a support;    a back bracket for attachment to a chair back, said back bracket pivotally mounted to said support at a first pivot;    a seat plate extending above said support, said seat plate for attachment to a chair seat, said seat plate pivotally mounted to said back bracket at a second pivot and slidably hinged to said support at a third pivot,    said second pivot positioned above said first pivot and either forwardly or rearwardly of both of said first and third pivots such that rearward titling of said back bracket draws said seat plate rearwardly and tilts said seat plate rearwardly.